The Flocking Difference
My Kowa Prominar 500mm f/5.6 always had some constrast issues in backlit scenes. I suspected that stray light bouncing off the rear tubes was part of the problem. The lens has an abnormally large image circle to support the 350mm field of view with the reducing adapter. The light from the extended image circle will strike the walls of the rear tubes and make their way to the sensor.
The first section of tube is right behind the rear element. The walls are blackened, but they lack any threading or baffles. I applied some self-adhesive flocking to this section as well as the bayonet mount.
The second section is in the picture above. The inside is threaded, but the threading wasn't done correctly. It needed to be cut deeper to minimize the surface area of the tops of the threads. It would have been even better if they used a coarser thread. Only the end of the tube got illuminated, so I only flocked that part. You can see how the flocking is so much darker than the threading. I also flocked the bayonet mount.
The last section is the EOS to Nikon Z mount adapter. I added flocking to the inside surfaces as well, but the effectiveness was not so great. The angle of incidence was too low for it to be much more effective than the threading.
The flocking made some difference, but it was less than I had hoped/
Sunnyvale, CA
The Flocking Difference
My Kowa Prominar 500mm f/5.6 always had some constrast issues in backlit scenes. I suspected that stray light bouncing off the rear tubes was part of the problem. The lens has an abnormally large image circle to support the 350mm field of view with the reducing adapter. The light from the extended image circle will strike the walls of the rear tubes and make their way to the sensor.
The first section of tube is right behind the rear element. The walls are blackened, but they lack any threading or baffles. I applied some self-adhesive flocking to this section as well as the bayonet mount.
The second section is in the picture above. The inside is threaded, but the threading wasn't done correctly. It needed to be cut deeper to minimize the surface area of the tops of the threads. It would have been even better if they used a coarser thread. Only the end of the tube got illuminated, so I only flocked that part. You can see how the flocking is so much darker than the threading. I also flocked the bayonet mount.
The last section is the EOS to Nikon Z mount adapter. I added flocking to the inside surfaces as well, but the effectiveness was not so great. The angle of incidence was too low for it to be much more effective than the threading.
The flocking made some difference, but it was less than I had hoped/
Sunnyvale, CA